Mac - Game Completely Unplayable

I received my copy of The Walking Dead as a gift through Steam for Christmas. It worked fine for a while, until I started having some problems with the save. It would "forget" that I had completed parts of a chapter or something. Moving prefs.prop files worked flawlessly for a while and I got pretty far into Episode 4.

A friend came over and I let her play the entire first episode on a second save slot. After dinner we rebooted the game and her entire game slot was wiped. Tried moving prefs.prop files. Didn't work.

Few days pass and I tried to continue my progress on Episode 4. I click on the save file, and the screen goes black but the cursor is visible. I hear ambient sounds (like wind blowing and groaning, or something). But the game is 100% unplayable. I tried starting a new slot on Episode 4, messing around with the prefs.prop files some more, and deleting the game and reinstalling (which did nothing -- my useless saved Episode 4 slot was still there).

My game is 100% completely unplayable. I cannot do anything with it and I'm getting really frustrated. Does anyone have any ideas?

I tried to find the savegame with the most progress, but i could not get any savegame after save_37.save to run, using workarounds.

You should be able to get it to load by rewinding to "Episode 3, Chapter 7: Making Plans". That means, some progress is lost, but at least you should be able to continue with most of your decisions made so far.